HS APFS on external USB drive doesn't boot on some macs

Discussion in 'macOS High Sierra (10.13)' started by chmedly, May 19, 2018.

  1. chmedly macrumors newbie

    Sep 14, 2006
    So, I had a 2012 MBP with an M500 SSD drive formatted APFS with High Sierra running fine. I removed the drive and put it in an external USB3.0 enclosure. I've found that this drive is not seen and won't boot by a 2010 13" MBP and a Late 2013 15" rMBP but WILL BE SEEN AND BOOT by an Early 2013 13" rMBP. I can't find any rhyme or reason for this. Any thoughts?

    Also, my intention was to install this drive in the 2010 MBP. But this computer doesn't see the APFS drive to boot whether installed internally or via the USB enclosure. On top of that, I've had trouble installing anything but Yosemite in the computer. El Cap, Sierra and High Sierra give me issues. The High Sierra USB installer for instance, won't even boot the computer. And I tried two different downloads of the installer on two different USB 3 sticks.
  2. CoastalOR macrumors 68020


    Jan 19, 2015
    Oregon, USA
    My first thoughts are that some Macs require a EFI or SMC firmware update to run High Sierra. Normally running the HS installer can also update the firmware, but since you are not running the installer on the other Macs they may not have the latest/needed firmware.

    Here is a Apple Support article to check if your Macs have the latest firmware:
  3. treekram macrumors 68000

    Nov 9, 2015
    Honolulu HI
    The problem with this article is that Apple is no longer updating it. The article date is the same date as the introduction of High Sierra and I believe most if not all of the EFI updates required by High Sierra were released before the High Sierra release. So if you have a EFI version equal to or greater than what's in the article, it should have APFS support - if the Apple article was correct as of it's publish date.

    (By the way, if you have an early 2010 MBP, the late 2010 MBP is the earliest MBP which can officially run High Sierra.)

    If you try to install High Sierra and it requires an EFI update, it should say so in the installation. You should have AC power connected. If the EFI version is the issue and if you applied updates in the past on battery power, that maybe why it didn't do an EFI upgrade.

    If the EFI is not the issue, I don't have any ideas as to why it would run on the early 2013 MBP not not the late 2013 MBP.

    I have had issues with OS installs using a USB flash drive so I do it from a regular OS running the install app (sometimes the install app is on an external HD).
  4. toru173 macrumors regular

    Apr 5, 2007
    The macOS High Sierra updater will apply the EFI update to the MLB when initiating the software update. EFI updates were packaged with the installer for almost every Mac that supported High Sierra. The update app applies the EFI update, then copies the OS update files across, then applies those.

    Unless the target logic board has been given the EFI update treatment, it won't boot APFS formatted drives. If you want to get it to boot the drive you can force the update manually, but you will permanently update the logic board of the target computer - this may not be desirable! You will need a small Sierra OS install and a copy of all the firmware updates (found in the installer) if you wish to manually apply the update on each device you want to boot your APFS formatted High Sierra install on.

    However, an easier option is to take a backup, reformat your drive to HFS, re-install High Sierra and restore from your backup. Good Luck!

Share This Page